Low voltage circuit breakers or circuit breakers for short are known and are used for energy distribution up to 6300 Amperes in low voltage switchgear as incoming feeder circuit breakers or outgoing branch circuit breakers. The term circuit breaker characterizes a mechanical switching device which can switch on, carry and switch off currents with the aid of an electronic overload trigger under operating conditions in the circuit. They are also used as switching and protection devices for motors, capacitors, generators and transformers however, but can also be used as emergency stop switches.
With the circuit breakers the current is compared with a threshold current in each case and the circuit breaker is triggered if the threshold current is exceeded by a predetermined value, with the exceeding of the threshold current serving as an indication of the presence of a short circuit. The exceeding of the threshold current can however also be triggered in another way, e.g. through switching processes which are linked to an overcurrent in a similar manner to a short circuit. Frequency converters can also cause overcurrents that, interpreted as short circuits, would lead to the triggering of the circuit breaker.